Day: June 21, 2014

For several years now, filament-based plastic printers have ruled the hobbyist market, with a new iteration on squirting plastic appearing on Kickstarter every week. SLA printers, with their higher resolution and historically higher price for raw materials, have sat in the background, waiting for their time to come.

Now, with the Sedgwick printer now available on Kickstarter, we may finally be seeing some resin printers make their way into hackerspaces and workshops the world over. Instead of other DLP projector-based resin printer where projector light shines up through the resin tank, the creator of the Sedgwick, [Ron Light] is doing things the old-fashioned way: shining the projector down onto the surface of the resin. He says it’s a simpler method, and given he’s able to ship a Sedgwick kit minus the projector for $600, he might be on to something.

There are a few other resin printers coming on the scene – the LittleSLA will soon see its own Kickstarter, the mUVe 1 is already shipping, and over on Hackaday Projects, the OpenExposer project is coming along nicely. All very good news for anyone who wants higher quality prints easily.

Ten years ago, [Trixter] created 8088 Corruption, a demo for the original PC, the IBM 5150, that displayed full motion video using a CGA card and a SoundBlaster. It was hailed as a marvel of the demoscene at the time, garnered tons of hits when it was eventually uploaded to Google Video, and was even picked up by the nascent Hackaday.Now, ten years later, and seven years after [Trixter] said full motion video using the graphics mode of a CGA adapter was impossible, he’s improved on his earlier work. Now, it’s possible to display video at 640×200 resolution at 30 frames per second on a 30-year-old computer.

[Trixter]’s earlier work used the text mode of the CGA adapter, only because the 40×25 character, 16 color mode was the only graphics mode that could be entirely updated every single frame. It’s still one of the high points of the PC demoscene, but from the original video, it’s easy to see the limitations.

A while back, [Trixter] said displaying video using his computer’s graphics mode was impossible. He’s had years to think about this statement, and eventually realized he was wrong. Like the developers of modern video codecs, [Trixter] realized you don’t need to change every pixel for every frame: you only need to change the pixels that are different from frame to frame. Obvious, if you think about it, and all [Trixter] needed to do was encode the video in a format that would only change dissimilar pixels from frame to frame, and manage the disk and memory bandwidth.

After reencoding the 10-year-old demo for graphics mode, [Trixter] turned toward his most ambitious demo to date: playing the ‘Bad Apple’ animation on an 8088. As you can see in the video below, it was a complete success.

In high speed digital circuits, fast doesn’t necessarily mean “high clock rate”. [Jack Ganssle] does an excellent job at explaining how the transition time of signals in high speed digital circuits is just as important as the speed of the signal itself. When the transition time is large, around 20 nanoseconds, everything is fine. But when you cut it down to just a few nanoseconds, things change. Often you will get a ringing effect caused by impedance mismatch.

As the signal travels down the trace from the driver and hits the receiver, some of the signal will get reflected back toward the driver if the impedance, which is just resistance with a frequency component, does not exactly match. The reflected signal then heads back to the driver where the impedance mismatch will cause another reflection. It goes back and forth, creating the ‘ringing’ you see on the scope.

[Jack Ganssle] goes on to explain how a simple resistor network can help to match the impedance and how these should be used in circuits with fast transition times, especially where you will be taking readings with a scope. As the scope probe itself can introduce impedance and cause the ringing.

With Independence Day just around the corner, American hackers are likely to find themselves blowing things up in the name of Independence. It’s all great fun but it can also be dangerous. The standard ignition method of “use a lighter and run away really fast” is not exactly safe. Instead of lighting your fireworks the old-fashioned way, why not follow [Facelesstech’s] example and build your own infrared controlled remote igniter?

The first step was to decide how to actually ignite the firework fuse. [Facelesstech] had seen others use a car cigarette lighter for this purpose and he decided to follow in their footsteps. He started by removing the cigarette lighter from his own car and pulling it apart. Only one component was needed for this hack. The main heating element is a small disk with a “stem” on the end. If you apply 12V to the stem and attach the outer edge of the disk to ground, the igniter will quickly become hot.

[Facelesstech] originally thought he could just solder some wires to the device. However, the heating element gets so hot that the solder just melts every time it’s turned on. He then got creative and drilled a hole in a small block of wood that fits the heating element. The element is bolted into the wood and the bolt is used as a conductor for the electrical power.

The heating element is powered via a 12V relay. The relay is controlled by an Arduino Nano. The Nano allows two modes of operation. With the first mode, you simply press a button and the Nano will start a five second timer. The idea is to give you enough time to run to a safe distance before the firework is ignited. This isn’t much different from the old-fashioned method, but it does give you a slightly extended fuse. The second mode is where the project really shines. The Nano is also hooked up to an infrared receiver. This allows [Facelesstech] to press a button on an old television infrared remote control to active the igniter. This is a clever solution because it allows you to get to a safe distance without having to run a long wire. It’s also simple and inexpensive. Be sure to watch the video test of the system below. Continue reading “Infrared Controlled Remote Firework Igniter”→

There is nothing better than a project that you can put on display for all to see. [Tristan’s] most recent project, a Decorative LED Matrix Frame, containing 12×10 big square pixels that can display any color, is really cool.

Having been built around a cheap IKEA photo frame this project is very doable, at least for those of you with a 3D printer. The 3D printer is needed to create the pixel grid, which ends up looking very clean in the final frame. From an electronics perspective, the main components are a set of Adafruit Neopixel LED strips, and an Arduino Uno with an Ethernet shield. The main controller even contains a battery backup for the real time clock (RTC) when the frame is unplugged; a nice touch. Given that the frame is connected to the local network, [Tristan] designed the frame to be controlled by a simple HTML5 interface (code available on GitHub). This allows any locally connected device to control the frame.

Be sure to check out the build details, they are very well done. If you are still not convinced how cool this project is, be sure to check out a video of it in action after the break! It makes us wish that you could play Tetris on this frame. Very nice job [Tristan]!

I was recently in Georgia for a for a non-HaD reason. This was my first trip to Georgia and it was hot, really hot, something I’m not too accustomed too. They also have nice condition roads there, something else I’m not accustomed too. I did have some free time while down there so I hopped on hackerspaces.org to see what was around. There were several spaces that were within driving distance but Freeside Atlanta was the only one that had an open event while I was available. That was the sole reason for my decision to stop in and I’m glad that happened because I had a great time.

Not long after entering I was greeted by a member, my new pal [Steven], who turned out to be the president of the group. After a quick exchange of pleasantries [Steven] started showing me around. My first impression was that the place was inviting. It seemed pretty big and there was little clutter. There were plenty of tables for working on your project and shelves with parts and components. These spare parts were not piled all over the shelves but were in boxes labeled with what was inside. I liked this because it was neat, tidy and it would be easy to find exactly what you were looking for. I know from experience that keeping this level of organization is hard in a community workshop environment.

Getting back to the tour, I was shown a separate dedicated classroom that holds 16 students, complete with dry erase boards. I passed a bunch of open work areas and tables as we continued into the space. A little further down there was a lounge area with couches and a huge projection screen next to the kitchen where I enjoyed some member-baked cookies. At that point I thought I had seen the entire space, but I was wrong, there was another door along what I thought was the back wall. That is the entrance to the shop area.

The front part of the space was pretty big, the shop was at least as large. I later found out that the entire place is about 5500 sqft. They have a pretty capable wood shop with work benches, a table saw, miter saw, planner, etc, not to mention plenty of hand and power tools. Moving a little further back there is a metal shop complete with mills, lathes and welders. There’s also a little CNC Router for cutting out parts. If this wasn’t enough so far, there’s a CO2 laser cutter, which was my favorite part of the tour….

Arduino has made a name for itself by being easy to use and has become an excellent tool for rapid prototyping of an idea. If one wakes up in the middle of the night in a eureka moment and hammers out a contraption – using an Arduino as the brains is about as fast and easy as it gets.

With that said, the WIDGEDUINO aims at making this process even faster and easier. Bristling with an array of meters, graphs and data entry widgets, the WIDGEDUINO is sure to be a hit with hackers, makers and engineers alike.

It’s based on the .NET framework and was designed with Visual Studio Windows Presentation Foundation. The user simply writes a sketch using the WIDGEDUINO library, and connects to a PC via serial or Ethernet to gain access to the assortment of awesome widgets.

You can find a few examples here. We hope the creators will keep us updated on the progress of this impressive project. Be sure to stick around after the break for a video demonstrating what the WIDGEUINO can do.